the purpose is to stop a child pulling over the cooker over a small amount and thus tipping hot water/food onto themselves.
the hose has to be in a certain position to avoid kinks and dragging on the floor. the old hose connection has to point 6/12 o clock to avoid kinks and thus wear, which is why mulitipoint hoses are popular as they swivel and thus hang straight.
there are dozens of other dimensions, mostly regarding proximity to combustible surfaces/worktops and safety features in the cooker itself to check ie flame safety devices like fires,boilers etc
this is after the overcharging fitter has considered your safety as regards ventilation and flueing
would you like to reconsider your complaint and give the guy a chance, he has paid a fortune in training with retests every 5 years that are never less than �1000 and a week off work for the test